Electrical m easuring-instrument



(NoModel.) 2 Sheets-Sheet 1 A E. WESTON. ELEGTRIGAILMEASURINGINSTRUMENT.

No. 529,435. Patented Nov/2o, A1894.

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E. WESTON.

ELECTRICAL MEASUEINE INSTRUMENT. f

No; 529,435 Patented Nov. 2o, 1894.

Unire STATES Amer rtree.

EDIVARD VESTON, OF NEVARK, NEW JERSEY.

ELECTRICAL lVlEASURING-INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 529,485, dated November20, 1894.

Application filed June 2l, 1894. Serial No. 515,232. (No model.)

To all whom if may concern.'

Be it known that I, EDWARD WESTON, of Newark, Essex county, New Jersey,have invented a new and useful Improvement in ElectricalMeasuring-Instruments, of which the following is a specification.

The invention relates to that class of measuring instruments which areknown as edgewise instruments, such as set forth in my application forLetters Patent, No 522,950, July 10, 1894.

VThe invention consists more especially in the construction andarrangement of the case of the instrument and in the disposition of theworking parts therein whereby the facility of manufacture of theapparatus is increased and the relation of the several portions thereofmade certain and definite.

In the accompanying drawings Figure l exhibits the interior of theinstrument, one side of the case being removed, and also shows thescale-plate and handle in section. Fig. 2 is a section on the line 2-2of Fig. l. Fig. 3 is a section on theline 4 4 of Fig. 4. Fig. 4 is aplan View in detail of the working mechanism of the instrument showingthe mode of connecting together the magnets, pole pieces and bracket.Fig. 5 is a top View of the instrument. Fig. 6 is a face View. Figs. 7and S represent respectively the two parts of the containing case of theinstrument.

Similar numbers of reference indicate like parts.

The case of the instrument consists of an iron casting which is made intwo portions, the said two portions being shown in Figs. 7 and 8. Thesetwo portions are put together so that the part which is shown in Fig. 8forms substantially a cover for the part which is shown in Fig. 7. Thepart which is shown in Fig. 7 has a flat face, 1, which is provided witha broad flange, 2, which flange forms the periphery of all of the caseexcept the convex face 3. The face 1 also has a narrower flange, 4.Referring now to the part which is shown in Fig. S, here there is a flatface, 5, similar to face l, and a flange, 6, similar to flange 4. Whenthe two parts of the case are put together, the face 5 comes in contactwith the broad flange 2, but the combined widths of flanges 4 and G areless than the Width of flange 2, so that a slot or space is left betweenthe flanges 4 and 6, as shown at 7, Fig. 2. All around the rim-of theflange 2 is formed a strengthening rib, 8, upon which are projections,9, which extend transversely of the flange 2. In these projections areapertures to receive the fastening screws or bolts by means of which thetwo parts of the case are connected together. The object of'the rim 8and projections 9 is to strengthen the casting and to prevent anywarping or other deformation thereof; also, by this means the castingmay be made thinner and lighter. Inside of the flanges 4 and 6 arestrengthening ribs, l0, the purpose of' which is the same as last abovestated.

It will be seen that by the foregoing construction I produce a case ofquite thin iron, which completely incloses all of the Working mechanismof the instrument, but which has a slot or opening extendinglongitudinally through its convex face 3. Suchacase is not only verystrong and rigid, but it serves as a magnetic screen, preventing theeffects of induction upon the magnets inclosed within. Upon the outerperiphery of the case is secured a rack-bar, ll. This bar is a separatecasting and is attached by means of screws, l2, as shown in Fig. 5;also, upon the case is secured a handle, 12*, and, at the opposite sideof the handle 12, is fastened a yoke, 13. The object of the yoke 13 isto support thecase upon a pivot on the switchboard, in an openinginwhich the instrument is received. The object of the handle is to tiltthe instrument on its pivot. The object of the rack-bar 11 is to receivea screw or pin on 'the switchboard which enters between any two teeth,and thus holds the instrument in any position in which it may beadjusted when swung forward or back on its pivot.

The arrangement of this instrument in the switchboard, as abovedescribed, is fully explained and illustrated in my Letters Patent No.522,950 aforesaid. The arrangement of the handle 12* and yoke 13 is thesame as described in said patent, and the general conformation of theinstrument is also the same. The rack-bar 11 is different, in that in myformer construction I used a bar having a series IOO of openings intowhich the end of the fastening screw entered. For this bar I nowsubstitute the rack-bar 1l.

I will now describe the general arrangement of the working mechanismwithin the case. Upon the inner side of the face l` is formed aprojection, 14, upon which is fastened, by means of the screw 15, atwo-'armed bracket, 16, Fig. 1. The arm of the bracket is curved, asshown,and terminates in a transverse bar, 17. To this bar are secured,by screws, l8, (dotted lines, Fig. 4) the pole pieces l9 of the magnets20. The pole pieces 19 are also secured together on the opposite sidefrom bar 17 by means of a bar, 2l, through which pass the screws 22. Themagnets 20 are fastened to their pole pieces by screws, 23, Fig. 4. Itwill be seen from the foregoing that the magnets 2O are thereforecarried by the bracket 16 and are thus held on a single support in aboutthe middle of the instrument case. The pole pieces 19 have concavefaces, so that a cylindrical space is formed between them. Symmetricallydisposed in this space is a cylinder, 24, of soft iron, which miscarried from the bar 21 by means of screws, 25. Upon the bars 17 and 21are projections, 26, Fig. 4, which enter between the ends of the facingpole pieces. The magnet poles are of course so disposed as to render thetwo pole pieces 19 of opposite'polarity. Supported on posts, 27, on thepole pieces 19, are bridges, 28. In these bridges are screw-steps, 29,in which screw-steps are received the pivots, 30, of a fine wire coil,31, which surroundsf the iron cylinder 24, and which, therefore, is freeto turn in the annular space between the cylinder 24 and the concavefaces of the pole pieces 19. This arrangement of coil, pole pieces andcylinder is one which I have ernbodied in many measuring instrumentshitherto patented to me, which instruments are now largely sold all overthe world and need no especial description. I propose to arrange, inconnection with the movable coil as herein described, a spiral spring orsprings for opposing or counterbalancing its movement, but

I do not show the spring or springs in the drawings, nor the means foradjusting them, since they form no part of my present invention,while,if referred to in detail, they would simply tend to obscure the partswhich I especially desire to show by making this description needlesslylong. The arrangement of such springs, together with the moving coildisposed in the annular field between the pole pieces and the soft ironcylinder will be found fully set forth in my Patents Nos. 392,386 and392,387, dated November 8, 1888.

Secured to one of the coil pivots is .the index needle 32. This needleextends through the slot 7, which I have already described asintervening between the flanges 4 and 6, in the case of the instrument.Upon the outer convex face of one flange is a scale, as best shown inFig. 6, and upon the outer convex face of the other Iiange are thenumbers representing units shown by said scale. `It will be observed,therefore, that I arrange the scale on one flange and the numbers on theother, and that the relation of the two anges is such that the slotthrough which the needle passes is on the median line of the instrument.This arrangement is preferable to that which is shown in my aforesaidpatent, where the slot is not on the median or central line, and henceboth the scale and the numbering are on one side of that line. On theoutside of the slot 7 there is secured to the needle 32 an index ormarker, 33, Fig. 6` which is here shown in diamond shape, softhat apoint of the diamond on one side traverses the scale divisions, whilethe corresponding point on the opposite side moves over the numbers.

On the front of the instrument is a frame, 34, which conforms in shapeto the convex face and has a single casting. lThis frame receives thecurved glass plate 35 which protects the scale. This frame is secured inplace in the following manner: The lower edge is received in a recess inthe upper portion of the yoke 13, so that the lower transverse bar, 36,of the frame rests between the yoke and the outer periphery of theflanges 4 and 6. The upper transverse bar, 37, of the frame has aflattened portion or flange 4l which enters a jog in the edge of thecase, as shown at 38. Above this transverse bar is a crossbar, 39, whichis formed integrally with the rack-bar 1l. From the foregoing it will beseen that in order to secure the frame 34 in place its lower bar, 36, isplaced in the recesses between the yokes and the face, and then theframe is adjusted in place. After that the rack-bar 11 is secured inposition by its screws 12. The handle 12* is fastened to the bar 39 bythe bolts 40.

It will be seen that the foregoing construction reduces the 'number ofparts of the instrument to a minimum and allows of their being veryeasily and conveniently assembled and taken apart. Thus all the workingmechanism may be constructed separately and is secured to the bracket16, which is fastened to the case by the single screw 15. In order toget at these working parts it is necessary only to remove that portionof the case which is shown in Fig. 8, so that the working parts thenbecome exposed, as represented in Fig. l. The outer frame and glass andthe rack-bar are easily applied in the manner already described. Theinstrument proper, therefore, may be said to consist really of tive,easily separable parts; namely, the working mechanism and its supportingbracket, the two castings forming the box or case, the outer framecarrying the glass and the rack-bar. The construction of the part of thecase shown in Fig. 7, having the strengthening ribs 9 provided withopenings for the fastening bolts or screws, is such as to lend itselfeasily to the use of special devices for locating these openings, sothat they will be invariably in position, and the IOO arrangement of thebracket 1G, in connection with the supporting projection l4, is such aslikewise to make the location between the mechanism of the instrumentalways invariable with regard to the case. It follows, therefore, thatall parts of the instrument come together in a definite and nnvariablerelation, without any possibility of relative displacement, and thus anyerror which might arise from this cause is completely eliminated.

I claimy l. A case for electrical measuring instruments formed of twoseparable parts, each part consisting of a side plate and a flange; thesaid parts being constructed substantially as set forth, so that, whenplaced together, the said flanges shall form a portion of the peripheryof the case, and so that between said flanges shall be left a slot oropening, substantially as described.

2. A case for electrical measuring instruments formed of two separateparts,one part consisting of the side platel l and flanges 2 and 4, andthe other part consisting of the side plate 5 and flange 6; the saidparts being constructed substantially as set forth, so that, when placedtogether, said flanges shall form the periphery of the case and so that,between said flanges 4 and 6 shall be left a slot or opening, 7,substantially as described.

3. A case for electrical measuring instruments formed of two separablemetal parts, one part consisting of the side plate 5 and flange 6 andthe other part consisting of the side plate l and flanges 2 and 4; theflange 2 having integrally formed upon the edge the rib 8; the saidparts being constructed substantially as set forth, so that, when placedtogether, said flanges shall form the periphery of the case, and sothat, between said flanges 4 and 6, shall be left a slot or opening, 7,substantially as described.

4. A case for electrical measuring instruments formed of two separablemetal parts, one part consisting of the side plate 5 and flange 6, andthe other part consisting of the side plate l and flanges 2 and 4; theflange 2 having integrally formed upon its edge the rib 8 andtransversely across its inner periphery projections, as 9; the saidparts being constructed substantially as set forth, so that, when placedtogether, said flanges shall form the periphery of the case, and sothat, between said anges 4 and 6, shall be left a slot or opening, 7,substantially as described.

5. A case for electrical measuring instruments formed of two separablemetal parts, one part consisting of the side plate 5 and flange 6, andthe other part consisting of the side plate l and flanges 2 and 4; thesaid flanges 4 and 6 having integrally formed strengthening ribs, l0;the said parts being constructed substantially as set forth, so that,when placed together, said flanges shall form and a slot or opening inthe median or central longitudinal line of said periphery, through whichslot the index needle of said instrument passes.

7. In combination with the working mechanism of an electrical measuringinstrument, a case inclosing said mechanism and having a portion of itsperiphery curved or convex, a longitudinal slot or opening in saidperiphery, through which slot the index needle of said instrumentpasses, a 'scale-marking on said portion on one side of said slot andscale numbers corresponding to said marking on the other side of saidslot.

S. In an electrical measuring instrument, the combination of a caseformed of two separable parts, each part consisting of a side plate anda flange, (the said parts being constructed substantially as set forth,so that, when placed together, the said flanges shall form a portion ofthe periphery of the case and so that, between said flanges, shall beleft a slot or opening,) working mechanism supported upon the inner sideof one of said plates, and an index needle actuated by said mechanismextending through said slot.

9. In an electrical measuring instrument, the combination of a caseformed of two separable parts, each part consisting of a side plate anda flange, (the said parts being constructed substantially as set forthso that, when placed together, the said flanges shall form a portion ofthe periphery of the case and so that between said flanges shall be lefta slot or opening,) a bracket supported upon the inner side of one ofsaid plates, working mechanism supported upon said bracketand an indexneedle actuated by said mechanism and extending through said slot.

lO. In an electrical measuring instrument the combination of acaseformed of two separable parts, each part consisting of' a side plate anda flange having a curved or con- Vex portion, (the said parts beingconstructed so that, when placed together, the said curved flanges shallform a portion of the case periphery and so that between said flangesshall be left a slot or opening along the median or central line of saidperiphery,) working mechanism supported upon the inner side of one ofsaid side plates and an index needle actuated by said mechanismextending through said slot.

1l. In an electrical measuring instrument the combination of a caseformed of two separable parts, one part having the side plate l and theflanges 2 and 4, the other part having the side plate 5 and flange 6,(the said IOO IIO

parts being constructed substantially as set forth so that, when placedtogether, said lianges shall form the periphery of the case and so thatbetween said flanges 4 and 6 shall be left a slot or opening, 7,) abracket, 16, secured upon the inner side of plate 1, working mechanismsupported by said bracket and an index needle actuated by said mechanismand extending through said slot.

12. The combination, in an electrical measuring instrument, of twopermanent magnets having like poles in contact, concave pole piecescommon to both magnets and disposed opposite to one another, a lixedcylindrical body of magnetic material supported between said polepieces, a coil surrounding said cylindrical body and rotating in theannular space between said body and said pole pieces, and an indexneedle actuated by said coil.

13. The combination with the inclosin g case of an electrical measuringinstrument containing a permanent magnet, a coil supported thereon andvibrating in the iield thereof and an index needle carried by said coil,of a bracket secured to the inner side of said case and to Said magnetand supporting said magnet and coil.

14. The combination, in an electrical measuring instrument, of themagnets 20, pole pieces 19, cylinder 24 supported in the space betweensaid pole pieces, pivoted coil 31, and index 32 carried by said coil,with the bar 17 secured to said pole pieces and bracket 16 carrying saidbar.

15. The combination of a case for -an` electrical measuring instrumenthaving a con vex face, 3, the frame 34 conforming in shape to said faceand received at one extremity in a recess in said case and provided atthe opposite end with a fiange, 41, and the bar 39; the said flangebeing confined between said bar 39 and the periphery of said case.

16. A case for electrical measuring instruments formed of two separablemetal parts, one part consisting of the side plate 5 and flange 6, andthe other part consisting of the side plate l and iianges 2 and 4 incombination with the rack or toothed bar 11 secured on the exterior offlange 2.

17. The combination of a case for an electrical measuring 'instrumenthaving a convex face, 3, the frame 34 conforming in shape to said faceand received at one extremity in arecess in said case and provided atthe opposite end with a flange, 41, and the rack or toothed bar 11secured to the exterior periphery of said case; the said flange 41 beingreceived and held between one end of said bar 11 and said caseperiphery.

EDWARD WESTON.

Witnesses:

Il. R. MOLLER, M. BosoH.

